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Biomedical subjects

J Barth

Publications and source records attributed to J Barth.

At least 127 records · Page 7Linked to original sources
PubMed1991

Pharmacokinetics and oral bioavailability of hydrocortisone.

The pharmacokinetics of 20 mg hydrocortisone were studied after IV and oral administration. Endogenous hydrocortisone was suppressed by dexamethasone administration. Hydrocortisone concentrations were measured in plasma and saliva. After IV administration, hydrocortisone was eliminated with a total body clearance of 18 L/hr and a half-life of 1.7 hr. The volume of distribution was 34 L. Oral bioavailability averaged 96%. Absorption was rapid, achieving maximum hydrocortisone levels of 300 ng/mL after 1 hour. Saliva levels were not proportional to plasma levels, but could be shown to reflect free, non-protein bound hydrocortisone concentrations in plasma.

Administration, Oral↗
PubMed1991

Pharmacokinetics and rectal bioavailability of hydrocortisone acetate.

The pharmacokinetics and bioavailability of hydrocortisone after rectal administration of a hydrocortisone acetate foam was determined. Endogenous hydrocortisone was suppressed by dexamethasone administration. Plasma levels were compared with those observed after iv and oral administration. Only a very small part of the rectal dose (100 mg) was absorbed; the mean absolute bioavailability was 2%. There was substantial intersubject variability. Maximum hydrocortisone levels were reached after 2 h and averaged 35 ng/mL. These levels were 10-fold lower than those obtained after oral administration of a fivefold lower dose (20 mg) of hydrocortisone in the same subjects.

Administration, Oral↗
PubMed1991

The effect of topical retinoids on the leukotriene-B4-induced migration of polymorphonuclear leukocytes into human skin.

Systemic retinoids are effective in a variety of inflammatory dermatoses. Disorders in which polymorphonuclear leukocytes (PMN) are involved, such as psoriasis and acne, respond particularly well to various retinoids. However, side-effects restrict the use of systemic retinoids to severe manifestations. Topical application might provide the possibility of avoiding the systemic side-effects of these compounds. In this communication we report on the modulation of transepidermal migration of PMN by topical application of all-trans-retinoic acid, 13-cis-retinoic acid, arotinoid methyl sulphone and arotinoid ethyl sulphone. Test areas of healthy volunteers were pretreated with these retinoids in a cream base and with corresponding placebo creams, and intraepidermal accumulation of PMN was quantified 24 h after epicutaneous challenge with leukotriene B4 (LTB4), using elastase as a marker enzyme. Topical treatment with 13-cis-retinoic acid resulted in a marked and statistically significant inhibition of the LTB4-induced migration of PMN. All-trans-retinoic acid, arotinoid methyl sulphone and arotinoid ethyl sulphone reduced the accumulation of PMN slightly, but not statistically significantly. Topical treatment with arotinoid methyl sulphone had no effect.

Administration, Topical↗
PubMed1991

Value of CD-1-positive cells in bronchoalveolar lavage fluid for the diagnosis of pulmonary histiocytosis X.

Pulmonary histiocytosis X is characterized by an accumulation of CD-1-positive histiocytosis X cells in the lung, which also can be found in the bronchoalveolar lavage fluid (BALF). However, it has recently been demonstrated that CD-1-positive cells can also be detected in BALF of patients with other interstitial lung diseases and in healthy smokers. We therefore examined the frequency of CD-1-positive cells in a pool of patients with different pulmonary disorders, according to their smoking habits and diagnoses. We have studied the bronchoalveolar lavage in patients with pulmonary histiocytosis X (n = 6), sarcoidosis (n = 88), and in 97 patients with other miscellaneous lung disorders by using the immunoperoxidase method to detect CD-1-positive cells on glass slides. All patients with histologically proven histiocytosis X displayed more than 5% CD-1-positive cells, whereas patients with other pulmonary disorders showed no more than 3.6% CD-1-positive BAL cells. The dividing line of 5% CD-1-positive cells was not influenced by patients' smoking habits. The identification of CD-1-positive cells in BALF appears to be useful in diagnosing pulmonary histiocytosis X.

Antigens, CD↗
PubMed1991

A selective LC/RIA for dexamethasone and its prodrug dexamethasone-21-isonicotinate in biological fluids.

A combined LC/RIA procedure is described for the selective determination of dexamethasone (DEX) and its prodrug dexamethasone-21-isonicotinate (DIN) in plasma. The low affinity of the employed dexamethasone antiserum for DIN (cross-reactivity less than 0.5%) allowed the direct determination of DEX in plasma extracts. For the determination of DIN, both substances of interest were separated by LC, the DIN containing fraction was collected, hydrolysed and the generated DEX was consequently assayed by radioimmunoassay. The assay detection limits were 0.1 ng ml-1 for DEX and 0.75 ng ml-1 for DIN. For both substances, inter- and intra-day variabilities (RSDs) were 6 and 12%, respectively.

Binding Sites↗
PubMed1991

Pharmacodynamics of methylprednisolone phosphate after single intravenous administration to healthy volunteers.

The pharmacokinetics and pharmacodynamics of methylprednisolone were investigated after intravenous administration of methylprednisolone phosphate to healthy subjects at seven different doses (16 to 1000 mg). Forty different pharmacodynamic parameters were followed for 1 week. The pharmacodynamic data were analyzed as a function of time as well as cumulative effects in form of the areas under the effect-time curves. Statistically significant dose-dependent effects of methylprednisolone were observed for 15 pharmacodynamic parameters. Highly significant (P less than or equal to 0.0001) effects were increases in glucose levels, number of white blood cells, and segmented granulocytes as well as a decrease in the number of lymphocytes. For these pharmacodynamic effects an integrated pharmacokinetic/pharmacodynamic model was derived that translates the methylprednisolone plasma concentration-time profiles into effect-time profiles. This model allows prediction of pharmacodynamic effects for any single dose in the range studied at any time point.

Adolescent↗
PubMed1991

An 8-week double-blind study of amlodipine and diltiazem in patients with stable exertional angina pectoris.

A multicenter, double-blind study was performed to compare the antianginal efficacy and safety of the new dihydropyridine calcium antagonist amlodipine with the benzothiazepine calcium antagonist diltiazem in patients with stable exertional angina pectoris. Following a 2-week placebo run-in period, 39 patients were randomized to receive amlodipine (2.5-10 mg once daily) and 41 patients to receive diltiazem (60-120 mg three times daily) in an 8-week double-blind treatment phase. The study used standardized bicycle exercise testing as a primary efficacy assessment. Patients also recorded angina frequency and nitroglycerin (NTG) tablet consumption/ week. Treatment with amlodipine and diltiazem resulted in an improvement in total exercise time, time to angina and total work, mean ST-segment deviation at maximum common load, median number of angina attacks/week, and NTG tablet consumption/week. The incidence and severity of possibly treatment-related side effects and laboratory test abnormalities were comparable for both drugs. The most frequently reported side effects were dizziness, headache, peripheral edema, and nausea. Two patients withdrew from diltiazem treatment due to pruritus in one case and severe headache and moderate dyspnea in the other. No amlodipine-treated patients withdrew due to side effects. In conclusion, this study demonstrated that the antianginal efficacy and tolerability of amlodipine is equivalent to diltiazem, but amlodipine has the advantage of once-daily dosing.

Adult↗
PubMed1991

Increased expression of growth factor genes for macrophages and fibroblasts in bronchoalveolar lavage cells of a patient with pulmonary histiocytosis X.

Pulmonary histiocytosis X is the local manifestation of a systemic disorder of unknown cause characterised by infiltration of Langerhans cell like histiocytes and parenchymal fibrosis. In a male smoker with histologically proved histiocytosis X and functional impairment bronchoalveolar lavage showed an increase in CD-1/OKT-6 antigen positive histiocytes to 8%. Northern blot analysis of RNA from bronchoalveolar lavage cells showed an exaggerated expression of the M-CSF gene and of the c-fms gene encoding for the corresponding receptor. An increased level of c-sis RNA, which encodes the B chain of platelet derived growth factor, was also found. Diffuse reticulonodular infiltrates on the chest radiograph resolved with glucocorticoid treatment and CD-1/OKT-6 antigen positive histiocytes fell to 3%. Macrophage colony stimulating factor, c-fms and c-sis gene expression were reduced almost to normal after treatment. The results suggest that macrophage colony stimulating factor and platelet derived growth factor may have a role in the initiation or maintenance of pathological reactions in pulmonary histiocytosis X.

Adult↗
PubMed1991

Alveolar macrophages in idiopathic pulmonary fibrosis display a more monocyte-like immunophenotype and an increased release of free oxygen radicals.

Bronchoalveolar lavage (BAL) was performed in 13 patients with idiopathic pulmonary fibrosis (IPF) and in 10 control subjects. Free oxygen radical (FOR) production of alveolar macrophages (AM) and of blood monocytes was measured by luminol-dependent chemiluminescence (LDCL) without and after stimulation with zymosan A. We confirmed earlier studies that alveolar macrophages of IPF patients display a significantly elevated release of FOR under basic and under stimulated conditions. In contrast to alveolar macrophages, blood monocytes did not reveal altered LDCL in IPF. This indicates that the functional properties for augmented FOR release by IPF alveolar macrophages are acquired in the lungs and not in the peripheral circulation. To elucidate the possible mechanisms leading to the augmented LDCL response, immunophenotyping of alveolar macrophages was carried out. A panel of new monoclonal antibodies of the Ki-M-series, discriminating differentiation stages of monocyte/macrophage subpopulations, served for immunocytochemical staining. In IPF patients distribution of Ki-M2, Ki-M3, Ki-M6 and Ki-M8 positive AM demonstrated an increased proportion of alveolar macrophages expressing a more monocyte-like immunophenotype. Normally, monocytes as precursors of AM reveal a markedly stronger LDCL than alveolar macrophages themselves. Therefore, it seems likely that the increased LDCL of alveolar macrophages in IPF is due to the higher proportion of more immature monocyte-like cells in the alveoli of these patients.

Antibodies, Monoclonal↗
PubMed1991

[Bronchoalveolar lavage in Wegener's granulomatosis].

Bronchoalveolar lavage was performed in 14 patients suffering from histologically confirmed Wegener's granulomatosis who also showed x-ray signs of lung involvement. Cell distribution and immunophenotypical characterisation of lymphocytes and alveolar macrophages of patients suffering from Wegener's granulomatosis were compared with the findings obtained from 10 controls. The bronchoalveolar lavage of the granulomatosis patients showed a significant increase of the total cell count, signalling inflammatory involvement of the lung. Differential cytgological analysis showed a significant increase in the total number of granulocytes in the lavage fluid of the Wegener's granulomatosis patients (in one case up to 40%). The median granulocyte count was increased fivefold compared with the control. The increase of the granulocyte count was mainly conditioned by an increase in the number of neutrophilic granulocytes but there was also a significant increase in eosinophilic granulocytes. There was also a slight but significant increase in the lymphocyte count in the bronchoalveolar lavage fluid of patients with Wegener's granulomatosis. The number of CD-3-positive lymphocytes was significantly higher than with the controls. No significant differences were noted for the CD-4-positive, CD-8-positive and CD-19-positive lymphocytes. Immunophenotyping of the alveolar macrophages with monoclonal differentiation markers of the Ki-M-Series showed that the alveolar macrophages of patients with Wegener's granulomatosis resembled an immunophenotype that was close to that of monocytes. The number of proliferating macrophages was also higher than with the controls.

Adult↗
PubMed1990

A prospective study of the accuracy of preoperative computed tomographic staging of patients with biopsy-proven rectal carcinoma.

From June 1983 to January 1986, 91 patients with biopsy-proven adenocarcinoma of the rectum had computed tomographic scans of the pelvis performed before treatment as part of a "sandwich" radiotherapy-surgery regimen. Two experienced diagnostic radiologists performed locoregional staging of all scans according to the University of California at San Francisco criteria; one of these radiologists repeated this staging at a later time to test the reproducibility of a single observer. Staging was performed without the use of any other radiographic studies or of any clinical information except the patients' age, sex, and the diagnosis of rectal carcinoma, to test the value of computed tomographic scans alone for staging. Agreement between the two stagings performed by the first observer was 51 percent, and interobserver agreement was only 37 percent. Agreement with Dukes' staging was only 33 percent. Therefore, preoperative pelvic computed tomographic scanning of primary rectal adenocarcinoma should not be relied upon for staging or for the selection of patients for treatment options.

Adenocarcinoma↗